Spring assemblies comprising pocketed coil springs are commonly used in seating or bedding products. Such pocketed spring assemblies are commonly made of multiple strings or rows of individually pocketed coil springs. Adjacent strings of individually pocketed coil springs are joined together by gluing or otherwise attaching the fabric of the strings of springs to each other. Pocketed coil springs are often referred to as a Marshall construction in which each coil spring is encased within its own fabric sack or pocket. The sack or pocket is typically defined between two plies of fabric strip connected together at intervals along transverse lines of attachment spaced along the strip. Pocketed spring assemblies are often supported by foam structure, such as by being inserted into a partial foam encasement or “bucket” as the term is used in the art. One or more upper layers of foam and/or other material may be located on top of the “bucket” to complete the foam encasement. Other constructions are also used to complete the product based on the inner pocketed spring assembly.
In order to provide edge support and reduce the amount of foam used in bedding products, Leggett & Platt of Carthage, Mo. has previously developed and sold a high density pocket coil border under the tradename Quantum Edge to replace foam borders. In this bedding product or mattress, interior coils formed in a central matrix of strings of coil springs have a larger diameter than outermost side coil springs that completely or at least partially surround the interior matrix of pocketed coil springs. The smaller diameter perimeter coils therefore provide border or edge support.
It is therefore an objective of this invention to provide a seating product that reduces the amount of foam used in the product and adds modularity or variability to the design of the pocketed spring assemblies used in the seating product, for various reasons specific to the use and construction of such seating products.